The phrase “put one’s back into it” typically means “make a strenuous effort”, according to Dictionary.com. And yes, effort during sex is often appreciated. However, if eventually approved by the Food and Drug Administration (FDA), the NES/T gel could change the meaning of putting your back into it when having sex. The gel, developed by the Population Council and NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), is supposed to go on a man’s back and shoulders, where it can then be absorbed into the bloodstream.

This NES/T gel, which has nothing to do with the Nestea Plunge, contains a progestin compound called segesterone acetate (with the brand name Nestorone) along with testosterone. The progestin is supposed to do the “contracepting” by blocking your testes, if you have them, from naturally producing testosterone. This is supposed to reduce “sperm production to low or nonexistent levels.” Ah, but what then will happen to the fire in the kiln without testosterone around? That’s why the gel also includes testosterone to keep other things at attention and going.

Through the clinical trial, scientists will attempt to determine how well this gel actually has your back. Two principal investigators (Christina Wang, M.D. at the Los Angeles Biomedical Institute and University of California Los Angeles Medical Center and Stephanie Page, M.D., Ph.D. at the University of Washington) will lead the trial, which will involve various investigators and sites from NICHD’s Contraceptive Clinical Trials Network and has a target enrollment of 420 couples. The trial will consist of 2 phases. For the first phase, male volunteers will try the NES/T gel each day for 4 to 12 weeks to see if they can tolerate the gel and if their sperm levels drop low enough. Those whose sperm levels still remain high enough for conception will continue to use the gel in this phase for up to 16 weeks. The next phase for those who can tolerate the gel and have low enough resulting sperm levels will be to connect with their partners and you know what for 52 weeks. Of course, the couples should not use other forms of contraception in the meantime.

There is certainly a need for more contraceptive options. A study published earlier this year in The Lancet Global Health estimated that 44% of pregnancies worldwide were unintended from 2010 to 2014. And it takes 2 to tango. Therefore,both partners should be responsible for ensuring adequate contraception. For men, the primary available modes of contraception have remained condoms, vasectomies, and abstinence for many years. But abstinence can be a problem when you are having sex, and vasectomies can have a certain finality to them. Therefore, condoms are frequently the option.

But many men have struggled with condoms, even though it is not the most complex technology out there. According to a National Health Statistics Report, from 2011 to 2015, only about a third (33.7%) of 15 to 44 year old men in the U.S. used a condom during their last sexual intercourse. And using doesn’t necessarily mean using well or even properly. As I wrote for Forbes previously, a significant number of men make mistakes such as wearing the condom inside out, wearing it only part of the time, not fully putting it on, and using a knife to open the condom package. Note, not being able to open a condom package without using a knife may not look so good to your partner.

As a result, other male contraceptive options, such as pills, injections, and of course this gel, are under development. In this TED Talk, John Amory, MD, MPH, MSc, Professor of Medicine at the University of Washington describe the need for and challenges of developing new male contraceptive approaches:

The fact that the NES/T gel has made it to the clinical trial stage is promising. However, as with any technology, it is important to consider the potential implications and pitfalls of a technology prior to its reaching the market, so that appropriate adjustments can be made. Regardless of how successful the NES/T gel is in lowering sperm levels, it will not prevent the transmission of sexually transmitted infections (STIs) like condoms. With many STIs on the rise, it will still be important to ensure that people who should wear condoms to prevent STIs don’t end up switching over to something like this gel. Moreover, how easy will it be to get your back? If you’ve ever tried to apply sunscreen on yourself, you know that your back and shoulders aren’t necessarily the easiest parts of your body to reach. Ensuring adequate application of the gel may be challenging, especially since back and shoulder size and shape can differ quite significantly. Plus, if your partner is the one who has to use the gel, how can you make sure that he has his back so that he can have yours?

Nonetheless, don’t let these limitations dampen your enthusiasm about this possibility. With so many unwanted pregnancies, more contraceptive options are needed and as Olivia Plana described for the American Journal of Men’s Health, more male contraceptive options could help change the dynamics of pregnancy prevention, providing “males with greater control over their own reproduction.” While male contraceptive science certainly has progressed since 3000 B.C. when they used goats’ bladders as condoms, it hasn’t exactly seen an explosion of new products over the past century.